Exercise tube



FIG. 1 is a front perspective view of the exercise tube.

FIG. 2 is a back perspective view of the exercise tube.

FIG. 3 is a front elevational view of the exercise tube.

FIG. 4 is an enlarged top plan view of the exercise tube.

FIG. 5 is an enlarged bottom plan view of the exercise tube; and,

FIG. 6 is a back elevational view of the exercise tube. 

The ornamental design for an exercise tube, as shown and described. 